What Two Cochrane Reviews Found About Infliximab for Crohn's Disease

When Crohn's disease does not respond well enough to standard treatments, the conversation about biologics usually starts with infliximab. It was the first biologic medicine approved for Crohn's and remains one of the most widely used worldwide. Yet patients are often left with a simple question: what does the evidence actually show?

Two Cochrane systematic reviews now provide the clearest available summary. One, published in 2023, examined trials of infliximab for inducing remission. The other, published in 2024, looked at whether infliximab keeps people in remission once they have achieved it. Together, the two reviews cover nineteen randomised controlled trials and more than 2,300 participants. This article explains what they found.

What Crohn's Disease Is

Crohn's disease is a long-term inflammatory bowel condition that can affect any part of the digestive tract, from the mouth to the anus. The NHS describes it as a lifelong condition characterised by periods of active disease, during which symptoms including diarrhoea, abdominal cramps, fatigue, blood in the stool, and unintended weight loss are present, and periods of remission, during which those symptoms ease significantly or disappear.

Unlike ulcerative colitis, which is confined to the large bowel, Crohn's can cause deeper inflammation that penetrates the bowel wall. When Crohn's is not well controlled, repeated flares can lead to complications including fistulas, strictures, or surgery. Achieving remission and then sustaining it is therefore a central goal of treatment.

For most people, treatment begins with anti-inflammatory drugs and corticosteroids, followed by immunosuppressants such as azathioprine or 6-mercaptopurine for maintenance. When those approaches do not work well enough, biologic medicines become the next step.

What Infliximab Is

Infliximab is a monoclonal antibody that binds and neutralises tumour necrosis factor-alpha (TNF-alpha), a signalling protein found at elevated levels in the blood, bowel lining, and stool of people with Crohn's disease. By blocking TNF-alpha, infliximab reduces the inflammatory cascade that drives symptoms.

The NHS lists infliximab as a biologic used in Crohn's disease when standard treatments, including immunosuppressants, have not worked well enough. It is given as an intravenous infusion in a clinical setting, typically at weeks 0, 2, and 6 to initiate treatment (the induction phase), and then once every eight weeks for long-term maintenance.

The originator medicine is sold under the brand name Remicade. Biosimilar versions, including CT-P13 (brand names Inflectra and Remsima), are now widely used. Biosimilars are approved medicines that have been shown to be highly similar to the originator in terms of safety and efficacy.

What the 2023 Cochrane Review Found on Inducing Remission

A 2023 Cochrane systematic review (Gordon M et al.; Cochrane Database of Systematic Reviews, 2023 Nov 20; pubmed:37982428; DOI: 10.1002/14651858.CD012623.pub2) examined infliximab for inducing remission in active Crohn's disease. It included ten randomised controlled trials enrolling 1,101 participants, with studies conducted between 1999 and 2019. Seven of the ten trials enrolled people who had not previously received a biologic.

Infliximab combined with purine analogues versus purine analogues alone. At weeks 24 to 26, combining infliximab with azathioprine or 6-mercaptopurine was approximately 1.92 times more likely to produce clinical remission than the immunosuppressant alone. The reviewers rated this as moderate-certainty evidence, meaning they have reasonable confidence in the estimate.

Infliximab alone versus placebo. At week 4, infliximab alone was around 4.55 times more likely to produce clinical remission than placebo. The reviewers rated this as low-certainty evidence because it comes from a relatively small number of trials and the estimate is imprecise. Low-certainty means the true effect could be notably different.

Infliximab alone versus purine analogues alone. At week 26, infliximab alone was approximately 1.50 times more likely to produce clinical remission than purine analogues alone (low-certainty evidence).

Biosimilar versus originator. The review found little or no difference in clinical remission or response between infliximab and CT-P13 at week 6, though this comparison was based on limited data (low-certainty evidence).

Fistulating Crohn's disease. The authors were unable to draw firm conclusions for this specific population because of insufficient trial data.

The overall finding is that infliximab, particularly in combination with purine analogues, appears more effective than purine analogues alone for inducing remission. The certainty ratings matter: the moderate-certainty finding for the combination is more reliable than the low-certainty estimates for infliximab alone.

What the 2024 Cochrane Review Found on Maintaining Remission

A 2024 Cochrane systematic review (Gordon M et al.; Cochrane Database of Systematic Reviews, 2024 Feb 19; pubmed:38372447; DOI: 10.1002/14651858.CD012609.pub2) examined infliximab for maintaining remission once it has been achieved medically. It included nine randomised controlled trials enrolling 1,257 participants, conducted between 1999 and 2022.

Infliximab versus placebo for preventing relapse. Infliximab was more effective than placebo at preventing clinical relapse. Among participants on infliximab, 56 percent relapsed during the maintenance period, compared with 75 percent of those on placebo. The risk ratio was 0.73, and the reviewers rated this as moderate-certainty evidence.

Infliximab combined with purine analogues versus purine analogues alone. Adding infliximab to purine analogues was considerably more effective at preventing relapse than purine analogues alone: 12 percent of participants relapsed on the combination versus 59 percent on the immunosuppressant alone (risk ratio 0.20; moderate-certainty evidence). This is a large difference, and the moderate-certainty rating means the reviewers are reasonably confident in the finding.

Biosimilar versus originator for maintenance. The review found limited data comparing the two directly for maintenance and could not draw firm conclusions about whether there is a meaningful difference.

Safety. The review found insufficient evidence to determine whether infliximab reduces or increases the risk of serious adverse events during maintenance compared with placebo or active comparators. The trials were not powered or designed to answer this question definitively.

What This Means for Patients

Together, these two Cochrane reviews provide the most comprehensive synthesis currently available for infliximab in adult Crohn's disease. The consistent finding across both is that combining infliximab with a purine analogue outperforms either treatment alone. This supports the clinical practice of using combination therapy in people who can tolerate both medicines.

The maintenance data are particularly informative. A relapse rate of 56 percent on infliximab versus 75 percent on placebo means that infliximab meaningfully reduces the risk of Crohn's returning, though it does not eliminate it. The combination with purine analogues reduces that risk further, though the absolute rates in any individual depend on disease characteristics, previous treatment history, and other factors.

What the evidence does not settle includes how infliximab compares head-to-head with other biologics now available for Crohn's disease, such as adalimumab, vedolizumab, or ustekinumab. It also does not address which patients are most likely to respond, how long treatment should continue, or what the best management strategy is when Crohn's relapses on infliximab. Those questions require a conversation with a gastroenterologist who knows your specific situation.

Biosimilar versions of infliximab appear equivalent to the originator based on the available data, though that comparison is currently limited by the number of studies.

If you have Crohn's disease and are wondering whether infliximab or a biosimilar version might be right for you, please speak with your doctor or specialist. Treatment decisions depend on your individual disease history, previous therapies, current disease activity, and other clinical factors that only your care team can assess. This article is an evidence summary for general awareness and does not constitute medical advice. Do not start, stop, or change any treatment based on what you read here.